Device for de-aerating liquids



Sept. 13, 1960 R. G. CUNNINGHAM ETAL 2,952,329

DEVICE FOR DE-AERATING LIQUIDS Filed Oct. 25,1957 2 Sheets-Sheet 2 N VENTORS 14/70 2017460 A. DIV/ 48526 BY nited States Patent 055cc PatentedSept. 13, 1960 DEVICE FOR DE-AERATING LIQUIDS Richard G. Cunningham andDonald E. Dahlberg, Edwardsville, IlL, assignors to the United States.of America as represented by the Secretary of the Air Force.

Filed Oct. 25, 1957, Ser. No. 692,506

Claims. (Cl. 183--2-.5)

The present invention relates generally to devices for de-aeratingliquids, such as lubricating oil, and, as illustrated herein, relatesmore particularly to a device wherein pressurized, aerated oil isutilized to energize a fluid motor which in turn is operativelyconnected to a centrifugal device which removes entrapped gases from theoil.

The present invention is concerned with the removal of entrapped gasesfrom fluid such as lubricating oil to permit immediate re-use of theoil. Aerated oil is unstable, and after aeration has reached arelatively high level, the oil will froth and hence will not be insuitable condition for use as a lubricant. Foaming or frothing presentsfurther difiiculties since the entrained air displaces oil in thepressure pump and consequently reduces the flow of oil to the engine at.lower altitudes but as the barometric pressure decreases the flow ratewill at first decline and then fail completely as higher altitudes areencountered. I

The present invention has as one of its objects the provision of aself-energized device which is effective to remove entrapped gas fromthe liquid and wherein the gasfree liquid is returned for re-use in thelubrication system. To this. end, one feature of the invention residesin a device for separating gases from liquids having a liquid operatedmotor and a member forming the rotor of a,

centrifuge having an oil passage. into the outlet passage. of the rotorand also means for conducting separated gases away from the oil passage.The illustrated embodiment of the invention provides means which areeffective to remove the air from the oil and for conducting the. freedgas away from the oil contained within annular passage in the centrifugeand conducting said freed gases to permit escape of the freed gases tothe atmosphere.

The present device provides an effective construction, of relativelyhigh efiiciency wherein large quantities of oilrnay be de-aerated by aunit of small size and weight.

Another object of the invention is to improve generally upon theconstruction and operation of devices for. deaerating liquids such aslubricating oil.

With the above and other objects and features in view, the inventionwill now be described with particular reference to the accompanyingdrawings which illustrate a preferred embodiment thereof and in which:

Fig. 1 is a schematic showing of a lubricating system of which thepresent invention forms a part;

Fig. 2 is a view in section of the device for de-aerating oil; and

Fig. 3 is a sectional view of an air pressure control valve.

Referring now to. the drawings, particularly Fig. 1, it will be notedthat this figure illustrates schematically the various components whichgo to make up; a lubricating and de-aerating system. De-aerated oil, orsubstantially gas-free oil, is stored in a tank having a conduit 12leading to an eduetor 14 and through a second conduit 16 to a pressurepump 18. The pressure pump 18 supplies lubricating oil under pressurethrough a conduit 20 to the lubricating system (not shown) of an engine22.

The engine 22 is schematically shown in Fig. l and repreeating oil tothe lubricating system of an internal combustion engine wherein the oildrains to a. suitable dry sump. As the oil collects in the sump, it isremoved therefrom by a scavenging pump 24 through a conduit 26 to acooler 28. The volumetric capacity of. the scavenging, pump 24 issubstantially in excess of the capacity of the. pressure pump 18. Theaerated cooled oil passes from the cooler 28 to a spring loaded by-passvalve 30, which is. so arranged that a portion of the aerated oil is feddirectly to a fluid motor 32 which is coupled with a centrifuge 34 and avalve 30 also feeds aerated oil to by-pass the fluid motor 32 through aconduit 33 directly to the. centrifuge 34.

De-aerated oil flows. from the outlet end of the centrifuge 34 through aconduit 35 and back to the eduetor 14.. Thus, de-aerated oil underpressure. is fed through the conduit 16 to the pump 18 and then throughthe conduit 20 to the lubricating system of the engine 22.. Thegas orair contained in the oil originally was removed by the centrifuge 34and, as will later become apparent, is, collected and passes through a.conduit 42 wherein flow of the separated gas is controlled by an airpressure regulating valve 40. As illustrated, the valve 40- iscontrolled. or regulated by a pressure sensing line 44 which isconnected to the oil outlet conduit 35. The separated air under normalconditions of operation is returned to the oil storage tank 10 to avoidloss of oil droplets which may be. carried over. The inlet 16 to thepressure pump 18. is pressurized above local ambient pressure by the.scavenging pump 24. The eduetor 14 serves to pump into the closed loopto replace oil consumed by the. engine and to replace any oil carriedfrom the centrifuge 34 by. the air vent line 46. The tank 10 isprimarily a source of make-up oil.

As shown best in Fig. 2, the aerated oil which has been. used toenergize: the liquid operated motor 32 enters the centrifuge34 through apassage 52 and mixes with aerated oil flowing through the by-passconduit 33 and into the by-pass 50 to the angular aligned passage 52 tothe cylindrical rotor 54 of the centrifuge 34- which is supported bybearings 56 located at each end of the cylindrical rotor 54 as willlater be described.

A hollow shaft 57 is attached to the head plate or cover 58 of the rotor54. A casing 60 is attached to the head 58 of the rotor 54 and surroundsthe sleeve 57 just referred to above.. The other end of the rotor 54 ispro-- vided with an end cover 62 towhich the other end of the casing 60is secured. The end cover 62 is supported on the right hand end bearing56 which in turn is mounted. on another stationary sleeve 66.

The entrance passage 52 through which aerated oil passes form the motor32 and into the centrifuge is provided with a short drive shaft whichtransmits torque to the. rotor 54. The head plate 58 of the cylindricalrotor is provided with an opening 72 which receives. one end connector70 and is keyed thereto. Aerated oil passes. from alined radial openings74, 76 in.- the sleeve 57 and the plate 58 and is guided toward the.other end of the rotor 54. by suitable guide vanes 80.

The aerated oil passes axially along the inner wall of the rotor 54until it strikes a stationary circular plate 82 air is caused to escapethrough the tube 94 since the air pressure within the casing space 98 isless than the air pressure within the rotor 54. For a particular rotorspeed and oil flow rate into the rotor, the oil level A or filmthickness is maintained as the result of the relation of the peripheryof the stationary circular plate 82 to the inner surface of the rotor 54and by the air pressure within the rotor 54 which is controlled by therate of How of freed air through the tube 42. If the air pressure in theouter shell becomes too high the thickness of the oil film in the rotorwill be reduced and poor separation of oil and air will result. On theother hand, if air pressure in the outer shell is too low, the rotor 54will tend to fill with oil and reduced separation of oil and air willresult.

The centrifuge head 53 is provided with shoulder 98 within which theouter end of the casing 92 is supported by the head 53. This casing 92surrounds the entire centrifuge and supports the outlet shaft 66 at theexit end of the centrifuge. Air that has been separated from the oil iscollected within the central chamber of the rotor and is forcedtherefrom through a pipe 94 which has been provided with a central holeor opening 96. The pipe 94 is supported by and passes through the wallof the rotor 60 and leads to an annular space 98 between the walls ofthe enclosing casing 92 and the outer wall of the rotor casing 60. Atthe lower side of the casing 92 there are provided several openings 102which communicate with an exhaust chamber 106 which is connected to theexit conduit 42 and through which the air and oil will escape to preventinternal flooding of the casing.

Referring now to Fig. 3, there is shown an air pressure control valve 40into which the air enters from the centrifuge into the lower portion 108of the valve through an opening 110. At the bottom of the valve there isprovided an air exhaust opening 112 above which there is mounted a guidefor the stem 114 of the valve 40. The valve 40 is provided with a valveseat 116 into which a conical portion 118 may be seated and which iseffective to regulate the proper flow of air. The valve 40 is providedwith a rod 120 which is connected with a plate 122 at the top of thevalve. The upper rim of the plate 122 supports a bellows 124, the otherend of which is secured to a plate 126 located in the upper portion ofthe valve 40.

The bellows 124 is normally urged to fully extended position by acompression spring 132 interposed between a lower plate 134 and theupper end plate 122 of the bellows 124. Lower plate 134 has a clearancehole 138 therein for allowing reciprocation of rod 120 therethrough andalso to allow the air pressure which escapes by conical portion 118 toact on the interior of the bellows 124. When the back pressure of the.de-aerated oil through the conduits 44 is suflicient to move the valve118 toward closing position, passage of air entering the valve 40 fromthe conduit 42 is reduced and subsequently stopped when the conicalvalve 118 is seated in the opening in the plate 116, The conical valve118 may be moved toward open position either by building up air pressurewithin the bellows 124 or by a decrease in the back pressure of the oilin conduits 35 and 44. Thus pressure is maintained within the centrifuge34 at a sub stantially constant level.

Having thus described our invention what we claim as new and desire tosecure to Letters Patent of the United States is:

t We claim:

1. A device for separating gases from liquids having in combination, anenclosing casing having inlet and outlet passages, a liquid operatedmotor powered by aerated liquid under pressure, a hollow rotor withinsaid casing driven by said motor and having passages from the interiorof said hollow rotor communicating with said in-' let passage, saidrotor having axial guide vanes for guiding flow of said aerated liquid,a tubular member extending through said rotor in a direction generallyperpendicular to the axis of rotation of said rotor, an opening in saidmember remote from the rotor wall through which gases separated fromsaid liquid may be trans mitted between said rotor and said casing,means forming an exit passage in said casing for said separated gases,and means for conducting said gas-free liquid to said outlet passage.

2. A device for separating gases from liquids having in combination, anenclosing casing having inlet and outlet passages, a liquid driven motorpowered by aerated liquid, a hollow rotor driven by said motor andlocated within said enclosing casing, means for directing said aeratedliquid from said motor to the interior of said rotor, axial guide vaneson the interior of said rotor to direct deaerated liquid toward a rotoroutlet passage, means for conducting gases freed from said aeratedliquid to the space between said rotor and the enclosing casing andthrough the outlet passages in said enclosing casing, and means fordelivering said gas-free liquids to said rotor outlet passage.

3. A device for separating gases from aerated liquids having incombination, an enclosing casing having inlet and outlet passages, aliquid operated motor, a hollow rotor operated by said motor and mountedwithin said enclosing casing, axially oriented internal guide vanes insaid rotor to direct flow of aerated liquid received in said hollowrotor, said vanes falling short of one end of the rotor, and means insaid rotor effective to direct the passage of said deaerated liquid awayfrom said rotor and into said outlet passage.

4. A device for separating gases from aerated liquids having incombination, an aerated liquid operated motor, an enclosing casingincluding an end wall having an outlet passage therein, a cover memberfor the other end of said casing having an inlet passage therein forpermitting passage of aerated liquid from said motor, a hollow rotorsupported within said casing and having radial passages leading to theinner surface of the wall of the rotor into which said liquid isreceived from said inlet passage, a tubular member extending through thewall of said rotor and enclosed within said outer casing, stationarymeans forming a passage for said deaerated liquid, an annular sleevemounted in said end wall for supporting said stationary means and forconducting deaerated liquid from said last-mentioned passage out of saidcasing.

5. A device for separating gases from liquids, an enclosing casinghaving an inlet passage for aerated liquid and separate outlet passagesfor gas-free liquid and the separated gases, a valve means connected tosaid outlet passages, a pressure responsive member in said valve means,said valve means having a first chamber connected to said outlet passagefor gas-free liquid an a second chamber connected to said outlet passagefor separated gases, said first and second mentioned chambers beingseparated from each other by said pressure responsive member, means forbiasing said pressure responsive member, an outlet from said secondchamber for the passage of separated gas therefrom, a valve member forcontrolling passage of gas from said second chamber, and meansconnecting said valve member and said pressure responsive means to varythe position of said valve member to maintain a predetermined pressurediiferential between the liquid pressure and the gas pressure in saidoutlet passages of said casing.

References Cited in the file of this patent UNITED STATES PATENTS2,006,244 Kopsa June 25, 1944 2,441,631 Hills May 18, 1948 2,575,568Topanelian Nov. 20, 1951 2,575,923 McMahan et al. Nov. 20, 19512,664,170 Walker et al. vDec. 29, 1953

